Boiler tube cap



March 4, 1941. w. l. Buss 2,234,154

BOILER TUBE CAP n Filed Aug. 10. 1935 2 Sheets-Shoot l INVENTOR wm L15H68 BY.

ATTORNEY March 4, 1941. w L BLlss 2,234,154 l BOILER TUBE CAP Filed Aug.10, 1935 2 Sheets-Shoot 2 INVENTOR Wm. ..5//66 4 lllllllnn.. A .je j ,BYMm ATTORNEY Patented Mar. 4, 1941 UNITED STATES BOILER TUBE CAP WilliamL. Bliss, Niagara Falls, N. Y., assignor to USL Battery Corporation,Niagara Falls, N. Y.,

a corporation of New York Application August l0, 1935, Serial No. 35,658

1 Claim.

rhis invention relates to improvements in fluid heaters and vaporizers,and particularly in heaters of this sort in which the fluid circulatesthrough tubes While being heated, and in Which the tubes are connectedat their ends by headers or the like, the openings of which are sealedby means of closure plugs or caps.

It is a primary object of the invention to pro- Y vide plugs for handholes in boiler headers Which may be readily attached and removed fromthe header.

It is a further object of the invention to provide plugs for hand holesin boiler headers Which may be locked against rotary movement during theoperation of tightening or loosening the securing means thereof.

Heretofore considerable diiiiculty has been experienced in convenientlysealing the hand hole openings in boiler headers and this difficulty hasarisen after a short period of use by virtue of the fact that thevarious plug parts are locked t0- gether by corrosion so that it becomesvirtually impossible to remove the plugs Without a great dea1 of eiort.This annoyance is experienced principally with circular plugs which tinto circular openings. Such plugs turn With the clamping bolt and makethe seating and disassembly thereof extremely dimcult.

In order to overcome this difficulty, elliptical, pear-shaped, and otherirregularly shaped openings have been provided, but such openings areobjectionable in that they require the cutting away of a great portionof the metal in the rear wall of the header. Circular openingssubstantially the size of the tube holes are the most desirable in thatthey afford adequate Working space duringr the expanding operation ofthe tube and at the same time such circular openings permit the strengthof the rear Wall of the header to be maintained because they require theremoval of only a minimum amount of metal in their formation and permitof simpler and cheaper machining operations.

To the end that circular openings may be utilized and at the same timethe objections thereto may be overcome, this invention provides a handhole closure plug which may be locked against turning, both during theseating and removal of the plug.

To accomplish these objects, the invention consists in the features andthe combination or arrangement of parts hereinafter describedv andclaimed, reference being had to the accompanying drawings in which likereference numerals indicate like parts, and in Which:

Fig. 1 is a view of a portion of a liquid heater partly in section andpartly in full line;

Fig. 2 is a sectionalview through a portion of a header showing theimproved closure plug attached thereto;

Fig. 3 is an elevational view of a fragment of one of the headers; Fig.4 is an assembly view of one form of closure plug; and

Fig. 5 is a vieW of a slightly modified form of plug.

With detailed reference to the drawings, I0 indicates a furnacestructure having as a part thereof a fire box in which is positioned afire grate I2. The boiler drum I4 is supported on the top of the furnacestructure in a horizontal position as in the conventional construction.Water tubes I6 are inclined over the fire box and over the flue portionof the furnace in the rear of the re box, and these tubes are joined toa header I8 at their extremities.

The header I8 comprises a front Wall 20 having therein tube holes 22through which the tubes I6 are passed and into which these tubes areexpanded. A rear Wall 24 is joined to the front Wall 20 by means of sideWalls 26. In the rear Wall 24 at spaced intervals and in alignment withthe tube holes 22, are hand hole openings 28 which are provided for thepurpose, in the usual construction, of giving access to the interior ofthe header during the operation of expanding the tubes I6 into the tubeholes 22 and for the purpose of permitting subsequent tube cleaning.

The rear Wall 24 of the header I8 is provided at spaced intervals withdiamond-shaped openings 30 (see Fig. 3) which have a dimension overtheir longest part greater than the diameter of the hand hole closureplugs. Through these openings the closure plugs for a given head'er areamay be passed so that they may be positioned from the inside to obtainthe best joint for high pressure conditions Within the boiler underoperation.

The hand hole closure plug which constitutes this invention comprises abody portion 32 which is adapted to pass through a hand hole opening 28from the inside. 'I'he plug 32 is formed with a peripheral seat 34 whichis adapted to lie against the inside of the rear Wall 24 adjacent theopening 28. In most instances a gasket 36 may be provided between theseat 34 and the inner surface of the rear Wall 24. A spider or crow-foot38 having a plurality of legs 38' and having a centrally locatedaperture 40 is adapted to overlie a hand hole opening 28, and the legs38 are adapted to contact the rear Wall 24 at points surrounding a handhole opening 28. A bolt 42 is secured to the plug body portion 32 andpassed through the aperture 40 in the spider 38. This assembly isadapted to be drawn into close relation by threading a'nut on the bolt42 so that the seat 34 of the plug body 32 is drawn into tight relationwith the `rear wall 24 of the header. The parts as lthus far disclosedare more vor less conventional.

Inv order to prevent the body 32 of .the plug from turning either duringthe seating operation or during the removal thereof, this inventioncontemplates a locking means between the .body portion 32 and the spider38. y In the form shown in Fig. 2 of the drawings this locking memberconstitutes a key having a portion 44 parallel to the face of the bodyportion of the plug and rigidly attached thereto, and a leg portion 46at right angles to the body portion 44. The leg portion 46 issubstantially parallel to the bolt 42 and protrudes suiliciently farfrom the body portion 32 of theplug to extend between two adjacent legs38 of the spider 38.l

. In the modified form of the invention shown in Fig. the key is notattached to the body pontion of the plug, but is associated with thesame through the bolt 42. In this form of the invention the bolt 42 islocked to the body of the plug 32 in non-rotative relation and the key44 is aixed to thev bolt.

`In either the operation of seating or removing the plug the bodyportion thereof is effectively prevented from rotating with respect -tothe spider by contact of the legs 46 of the key 44 with either one ofthe adjacent spider legs 38. In use it may be desirable to manually holdthe locking key by means of a tool, as for example, a heavy Lbar oi'metal, one end of which may be inserted against two of the legs of thespider.

It is obvious that the principles herein dis- -closed may be capable ofvarious modifications in their application, and it is therefore desiredto limit this invention in no manner except as the exercise of the samemay be limited by the scope of the subjoined claim.

What I claim is:

A circular plug for use in a boiler header having a circular opening tobe closed, said plug -comprising a body portion adapted to pass into theopening, a peripheral seat on said body portion adapted to contact theinner side of the header adjacent the opening, a spider having aplurality of legs adapted to contact the header at the rear side of theopening, a bolt affixed to said body 'portion and extending through saidspider for drawing said seat into tight contact with the header, and akey having a portion parallel to said bolt xed to said bolt andextending Within its parallel portion between two adjacent legs of saidspider to prevent the turning of the plug with respect to said spiderduring the setting or removal thereof.

WILLIAM L. BLISS.

